It is desirable to reduce the temperature of chickens and other type poultry after the birds have been processed, or de-feathered, eviscerated, and are otherwise oven-ready and before the birds are packaged for delivery to the retail customer. A conventional poultry chiller 10, as shown in FIG. 1, is the “auger type” poultry chiller 10 which includes a trough-shaped, half-round tank 12 filled with ice water in which the auger 20 provides positive movement of the birds through the tank 12. The cooling effect for the water and the bird was originally provided by crushed ice added to the water. The later prior art designs included a counter-flow recirculation of the chilled water through the tank 12, with water being chilled by a refrigerated heat exchanger 40 instead of ice, as shown in FIG. 2. The water is introduced at one end of the tank 12, the outlet end 16, and flows progressively to the other end, the inlet end 14, where it is recirculated. In the meantime, the birds are continually delivered to the tank 12 and moved under the influence of the auger 20 in the counter-flow direction, and are lifted from the outlet end 16 of the tank 12 for further processing. A prior art poultry chiller of this general type is disclosed in U.S. Pat. No. 5,868,000, and the heat exchanger for the water refrigeration system suitable for this purpose is shown in U.S. Pat. No. 5,509,470.
As noted, chilled water is added to the tank 12 at the outlet end 16 of the tank 12, where the birds have been chilled and are being lifted out of the tank 12. The water flows against the birds in the opposite direction of movement of the birds, thereby assuring that the birds are always flowing into the cleanest water and that there is always a temperature drop between the temperature of each bird and the temperature of the water about each bird. Typical trough-shaped tanks 12 of the chillers 10 can be 5 to 12 feet in diameter and 15 to 150 feet in length. Frequently, one or more hanger bearings 30 are provided to assist in properly supporting the auger 20. Typically, the maximum space between hanger bearings 30 is approximately 35 feet.
As best seen in FIG. 3, the auger 20 is formed in segments and the hanger bearings 30 are located between the auger segments. A typical prior art hanger bearing 30 is supported by a horizontally extending upper structural support element 32 that is mounted at its ends to the sides of the trough and includes a downwardly depending central vertical support 33 and at its lower end an upper plate 31. A lower plate 34 is mounted to the upper plate and together they form an internal bearing surface (not shown). Typically, the segments of the auger 20 are connected by a horizontal shaft (not shown) which is received within the bearing surface, the bearing surface being sandwiched between the upper plate 31 and the lower plate 34, thereby transferring the weight of the auger 20 to the horizontally extending upper structural support element 32. Typically, the diameter of the horizontal shaft is smaller than the diameter of the auger shaft 22, thereby requiring the bearing surface of the lower plate 34 and the upper plate 31 and the vertical segment 33 of the hanger bearing 30 to be at least partially disposed between segments of the auger shaft 22. Therefore, the distance separating segments of the auger shaft 22 is limited by the dimensions of these elements. In turn, the distance separating segments of the helical flight structure 21 of the auger 20 is also limited by the dimensions of these elements. As well, because the upper structural support elements 32 typically used to provide support to the auger 20 extend across the tank 12 within the periphery of the helical flight structure 21, the structural elements 32 similarly dictate the separation required between independent segments of the helical flight structure 21. Separation between segments of the helical flight structure 21 are frequently on the order of 10 inches or greater.
One of the problems of existing hanger bearings 30 is that the interruption of the helical blade structure at the intermediate bearing location impedes the forward movement of birds through the poultry chiller. Also, it is possible that some birds will move backwards in the chiller due to the counter flow of water once a bird passes by the trailing edge of a segment of the helical flight structure. Those birds that move backwards about a segment of the helical flight structure require more time than is intended to move from the inlet end to the outlet end of the trough because they traverse the same segment of the chiller more than once. The reverse movement of these birds tends to create, or increase, the size of product surges traveling through the poultry chiller. The surges result in uneven unloading of the birds at the outlet end of the chiller, causing personnel handling the birds at the outlet end of the chiller to either speed up or slow down depending upon the output of birds from the chiller. In some cases, surges can require the addition of extra handling personnel. In those instances where personnel are not available, it is not uncommon for the birds to back up in the chiller discharge chute, causing birds to spill over the sides of the chute and handling tables positioned at the outlet end of the chiller. It is possible to collect these birds prior to spill over and place them in suitable vats and storage containers. However, for those plants that do not have additional handling personnel, or that don't respond quickly enough to the surges, the birds will frequently fall to the plant floor, leading to lost product and unsanitary conditions.
Another problem with typical hanger bearings is that the relatively large spacing required between independent segments of the helical flight structure (approximately 10 inches and up) allows birds to remain in the poultry chiller after processing is complete. These birds must be removed by handling personnel prior to cleaning the poultry chiller. Removal of the stranded birds increases the time required to clean the poultry chiller, thereby increasing the down time for cleaning the chiller. As such, fewer birds can be processed through the chiller for each production run. In addition to increased time and expense associated with the clean-up process, expense is incurred due to loss of product at the hanger bearing. Longer chillers require more hanger bearings to support the auger, thereby resulting in more frequent surging and increase product loss.
From the foregoing, it can be appreciated that it would be desirable to have a hanger bearing assembly for use with a poultry chiller that permits minimum horizontal displacement between segments of the helical flight structure. As well, it would be desirable if the hanger bearing assembly permitted spacing between the segments of the helical flight structure such that birds were prevented from moving through the chiller counter to their intended direction. Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.